Flutter iOS app submission issue warning: Missing Push Notification Entitlement - ios

Question

After uploading a Flutter app to App Store Connect, I got the following email warning:
Dear Developer,
We identified one or more issues with a recent delivery for your app,
"[APP NAME]". Your delivery was successful, but you may wish to correct
the following issues in your next delivery:
Missing Push Notification Entitlement - Your app appears to register with the Apple Push Notification service, but the app
signature's entitlements do not include the "aps-environment"
entitlement. If your app uses the Apple Push Notification service,
make sure your App ID is enabled for Push Notification in the
Provisioning Portal, and resubmit after signing your app with a
Distribution provisioning profile that includes the "aps-environment"
entitlement. Xcode does not automatically copy the aps-environment
entitlement from provisioning profiles at build time. This behavior is
intentional. To use this entitlement, either enable Push Notifications
in the project editor's Capabilities pane, or manually add the
entitlement to your entitlements file. For more information, see
https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/HandlingRemoteNotifications.html#//apple_ref/doc/uid/TP40008194-CH6-SW1.
After you’ve corrected the issues, you can use Xcode or Application
Loader to upload a new binary to App Store Connect.
Best regards,
The App Store Team
I don't use push notifications in my app? Why am I getting this warning? And how do I remove the "aps-environment" entitlement, wherever and whatever that is?
Note: This App Store issue has appeared multiple times on SO, sometimes because people needed to add push notifications (see this and this) and sometimes because they didn't (see this and this). This appears to be Flutter related in my case, though, so I am adding a new question.

Answer 1

Word on the street is that as long as you really don't use push notifications this will not cause your app to get rejected. So you can safely (?) ignore this warning and continue to submit your app.
This issue was described on GitHub here, and a solution is being discussed here. It's apparently somehow related to Flutter using the UIApplicationDelegate callback:
- (void)application:(UIApplication*)application
didReceiveRemoteNotification:(NSDictionary*)userInfo
fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler;
I'll let someone else explain the exact reason more clearly. Keep an eye on the GitHub issue.
For now I am just going to ignore the warning.
Update: I submitted my app, it was accepted, and there hasn't been any problem with it since then. So just ignore the warning.

Answer 2

As of today this problem is still not fixed in Flutter.
See the Issue 9984.
While this should not cause any rejects in the App Store it still needs to be fixed and there seems to be a workaround for this (also described in the issue above):
Add a file Runner.entitlements under ios/Runner/Runner.entitlements with this content:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>aps-environment</key>
<string>development</string>
</dict>
</plist>

Answer 3

My app does use push notifications so I wanted to make sure this was working. I found this post very helpful: Flutter/App Store Connect Warning: ITMS-90078 Missing Push Notification Entitlement
Open the Flutter project (Runner) in XCode.
Under Signing & Capabilities, press '+Capability' and scroll down to find Push Notifications.
XCode will generate the “ios/Runner/Runner.entitlements” file.
Done. My build appeared on next attempt.